Impact of digital technologies on human activities: Studies in the impact of digital technologies on human activities also is an important area of our research. For example, we are experiencing a new types of ethics in human-to-human communication using electornic mail systems. Another example is a reconsideration of the semantics of copyright. Do we still need to inherit current copyright semantics even if the semantics of publication change due to penetration of both online and offline digital publishing technology? These consideration are essential to the design of information systems since changes in common sense and design of information systems affect each other.

Our research topics focus on the development of the technologies which collectively provide a substrate for a better Information Environment, the everyday environment that assists users who wish to perform some creative task using advanced information systems. To meet this goal, we are conducting research in following areas. Parallel and Distributed Systems: There is growing interest in massively parallel systems as systems based on uniprocessors as tightly coupled parallel processors begin to approach their performance limits. We believe that proper utilization technologies for the emerging massively parallel systems are a key to a breakthrough in computational power. We are working on an operating system architecture for MPP systems, efficient implementation of the Linda system and distributed object programming. Networking Protocols and Systems: Among numerous research directions on networking protocols and systems, we are currently focusing on statellite communications and mobile computing. Development of a multicast transport protocol using the satellite communication channel is a vital request for today's internetwork. It will dramatically reduce duplicate flow of data over the same physical connection required for distribution of information that is potentially distributed to every node in the internetwork. NetNews and distribution of software in high demand are typical examples of such data.

In the area of mobile computing, we are trying to solve security issues represented by intended and unintended impersonation of logical addresses. We are also investigating possibilities of incorporating satellite channels for mobile communication. Information Handlinf Systems: While efficient delivery of information and position independent computing will provide a ceaseless stream of information, it may cause a problem called information flooding. A technology called information filtering, that filters out unnecessary information according to the given conditions, plays an important roll here. We are conducting research on an experimental prototype of an information filtering system capable of not only filtering out, but also picking up the information valuable to users based on their activity history.